Electric signal



Dec. 15', 1931. R w. DAY 1,836,452

ELECTRI C S IGNAL Filed Jun 4, 1927 Richard W My By @MfM AttorneyPatented Dec. 15, 1931 PATENT OFFICE RICHARD W. DAY, OF SEATTLE,WASHINGTON ELECTRIC SIGNAL Application filed June 4, 1927.

My present invention relates to an improved electric signal in thenature of a burglar alarm that sounds a warning when a key is insertedin the lock by an unauthorfi'ized person in an attempt to open a door,as

the front door of a house or dwelling.

The invention consists essentially in the use of an electrical conductorlocated within the lock casing of the door, in the path of the key thatis adapted to unlock the door, and the insertion of the key in thekeyhole causes the electrical conductor to complete an alarm circuitresulting in the sounding of a hell or other alarm. The electric signalcircuit and alarm bell are used in connection with the usual electricbell button for ringing the house bell and a control switch is providedwhereby the electric circuit for the signal or alarm may be opened orclosed to render the signal inoperative or operative as desired.

In the accompanying drawings I have illustrated one complete example ofthe physical embodiment of my invention wherein the parts are combinedand arranged according to the best mode I have thus far devised for thepractical application of the principles of my invention.

Figure 1 is a view showing portions of a door and its frame equippedwith the electric signal or alarm of my invention.

Figure 2 is an enlarged detail sectional view of a lock set for a frontdoor or outer door, with the bolt locked and the alarm set.

Figure 3 is a detail sectional view of one of the circuit makers,normally closed when the door is closed.

Figure 4 is a sectional view showing the conductor in the lock casingand one of the circuit makers between the door and frame.

Figure 5 is a diagram of the wiring in connection with the conductor.

Figure 6 is a perspective view showing the key inserted in the bushingof the conductor, the latter being pushed into position to make anelectrical contact when the key is shoved into the lock casing in anattempt to open the door.

In order that the general assembly and arrangement of parts may readilybe understood I have indicated a door 1 and its frame Serial No.196,594.

2 with the mortised lock-casing 3 having the usual knob-spindle 1, latch5, bolt 6 and keeper 7, the latter having the usual hole 8 as in Figure2 to receive the bolt 6 when the door is locked. The usual inner keyhole 9 and outer key hole 10 are provided in the lock casing, and theelectrical conductor 11 is located in the lock casing between these keyholes. The conductor is a metallic plate disposed horizontally in thelock casing with one end 12 fixed to a fixed insulation plate 13 on theinner side of one of the walls of the lock casing 3. The conductor isfashioned of resilient metal and its free end is provided with atransversely disposed bush ing 14 having end flanges 15 and alined withthe two key holes 9 and 10 in position to re ceive the key 16, or thefront end 17 of its shank. Thus, when the key is inserted in the outerkey hole 10, the end 17 enters the bushing 14 and continued pushing onthe key pushes the bushing into the inner key hole 9, the bushing actingas a guide for the key, and the key may be turned to unlock the door inusual manner. If the electric circuit for the alarm is open, thedoor-key unlocks the door in usual manner, but if the electric circuitis closed, the signal is sounded.

Two pairs of circuit makers, 18 and 19 and 20 and 21, carried by thedoor and its frame, form part of the electric circuits for the electrichouse bell and alarm bell, and are nor mally closed when the door isclosed. The members 19 and 21 that are secured in the door frame, or itskeeper plate 7, each comprise a metal terminal lug 22 having a frictionhead 23 that is flush with or projects slightly from the face of thekeeper. The movable members 18 and 20 carried by the door include each acasing 24, a plunger 25 movable longitudinally therein and a spring 26for normally projecting the plunger in position so that it willfrictionally engage the complementary head 23 of the fixed members 19and 21. The casings 24 of the spring plungers are fixed in the front 27of the lock casing 3 in position so that each plunger will engage astationary contact point on the frame when the door is closed.

The usual bell-button or switch 28 is used to ring the house bell 29,and the burglar alarm or bell is indicated as 30, a control switch 31being indicated for completing the circuit for either the house bell orthe alarm bell by contact with points 32 and 33 respectively. In Figure5 the switch is thrown to neutral position with both the house bell andthe signal bell out of operation.

The house bell circuit includes a battery 34 and extends from button 28through wire 35 to the circuit makers 1819, thence'by wires 36 to switch31 and point 32, thence by wire 37 to hell 29; by wires 38 and 39 to thebattery 34, and by wire 40 to the button.

The electric circuit for the alarm or signal extends from point 33 ofthe control switch by wire 41 to the bell 30, thence by wires 42 and 39to battery 2%, wire 43 to plate &4 and through'the conductor 11 and wire45 to circuit makers 2021 and wire 16 to the switch 81.

By manipulating the control switch from the neutral position of Figure 5either the house bell circuit may be completed for use, as by -day,orthe alarm circuit may be completed for use, as at night, or during theday when the house is unoccupied, and the alarm may be located in anydesired or convenient position to give a signal.

Having thus fully described my invention what I claim as new and desireto secure by Letters Patent is The combination in a circuit maker with acasing having key-holes in its opposite side walls, of a resilientconductor plate'within the casing having a fixed end and a movable freeend, a cylindrical bushing mounted transversely of the free end of theplate between the holes of the side walls, and exterior flanges at theopposite ends of the bushing, whereby the bushing is adapted to receiveand guide a door key from either end.

In testimony whereof I aflix my signature.

RICHARD W. DAY.

